Buggy code:
abstract class Tab { Shell shell ; Display display ; Button borderButton ; Button enabledButton ; Button visibleButton ; Button backgroundImageButton ; Button preferredButton ; Button tooSmallButton ; Button smallButton ; Button largeButton ; Button fillHButton ; Button fillVButton ; Composite tabFolderPage ; Group exampleGroup ; Group controlGroup ; Group listenersGroup ; Group otherGroup ; Group sizeGroup ; Group styleGroup ; Group colorGroup ; Group backgroundModeGroup ; final ControlExample instance ; static final int TOO_SMALL_SIZE = 10 ; static final int SMALL_SIZE = 50 ; static final int LARGE_SIZE = 100 ; static final boolean RTL_SUPPORT_ENABLE = false ; Group orientationGroup ; Button rtlButton ; Button ltrButton ; Button defaultOrietationButton ; static final int IMAGE_SIZE = 12 ; static final int FOREGROUND_COLOR = 0 ; static final int BACKGROUND_COLOR = 1 ; static final int FONT = 2 ; Table colorAndFontTable ; ColorDialog colorDialog ; FontDialog fontDialog ; Color foregroundColor ; Color backgroundColor ; Font font ; Combo backgroundModeCombo ; Button backgroundModeImageButton ; Button backgroundModeColorButton ; Text eventConsole ; boolean logging = false ; boolean [ ] eventsFilter ; Combo nameCombo ; Label returnTypeLabel ; Button getButton ; Button setButton ; Text setText ; Text getText ; static final String [ ] EVENT_NAMES = new String [ ] { "None" , "KeyDown" , "KeyUp" , "MouseDown" , "MouseUp" , "MouseMove" , "MouseEnter" , "MouseExit" , "MouseDoubleClick" , "Paint" , "Move" , "Resize" , "Dispose" , "Selection" , "DefaultSelection" , "FocusIn" , "FocusOut" , "Expand" , "Collapse" , "Iconify" , "Deiconify" , "Close" , "Show" , "Hide" , "Modify" , "Verify" , "Activate" , "Deactivate" , "Help" , "DragDetect" , "Arm" , "Traverse" , "MouseHover" , "HardKeyDown" , "HardKeyUp" , "MenuDetect" , "SetData" , "MouseWheel" , "Settings" , "EraseItem" , "MeasureItem" , "PaintItem" } ; Tab ( ControlExample instance ) { } void createControlGroup ( ) { } void createSetGetGroup ( ) { } void createControlWidgets ( ) { } void createColorAndFontGroup ( ) { } void changeFontOrColor ( int index ) { } void createOtherGroup ( ) { } void createBackgroundModeGroup ( ) { if ( ( getExampleWidgets ( ) . length ) == 0 ) return ; backgroundModeGroup = new Group ( controlGroup , SWT . NONE ) ; backgroundModeGroup . setLayout ( new GridLayout ( ) ) ; backgroundModeGroup . setLayoutData ( new GridData ( SWT . FILL , SWT . FILL , false , false ) ) ; backgroundModeGroup . setText ( ControlExample . getResourceString ( "Background_Mode" ) ) ; <START_BUG> backgroundModeCombo = new Combo ( backgroundModeGroup , SWT . CHECK ) ; <END_BUG> backgroundModeCombo . setItems ( new String [ ] { "SWT.INHERIT_NONE" , "SWT.INHERIT_DEFAULT" , "SWT.INHERIT_FORCE" } ) ; backgroundModeImageButton = new Button ( backgroundModeGroup , SWT . CHECK ) ; backgroundModeImageButton . setText ( ControlExample . getResourceString ( "BackgroundImage" ) ) ; backgroundModeColorButton = new Button ( backgroundModeGroup , SWT . CHECK ) ; backgroundModeColorButton . setText ( ControlExample . getResourceString ( "BackgroundColor" ) ) ; backgroundModeCombo . addSelectionListener ( new SelectionAdapter ( ) { public void widgetSelected ( SelectionEvent event ) { setExampleGroupBackgroundMode ( ) ; } } ) ; backgroundModeImageButton . addSelectionListener ( new SelectionAdapter ( ) { public void widgetSelected ( SelectionEvent event ) { setExampleGroupBackgroundImage ( ) ; } } ) ; backgroundModeColorButton . addSelectionListener ( new SelectionAdapter ( ) { public void widgetSelected ( SelectionEvent event ) { setExampleGroupBackgroundColor ( ) ; } } ) ; backgroundModeCombo . setText ( backgroundModeCombo . getItem ( 0 ) ) ; backgroundModeImageButton . setSelection ( false ) ; backgroundModeColorButton . setSelection ( false ) ; } void createEventConsolePopup ( ) { } void createExampleGroup ( ) { } void createExampleWidgets ( ) { } void createListenerSelectionDialog ( ) { } void createListenersGroup ( ) { } String [ ] getMethodNames ( ) { } void createSetGetDialog ( int x , int y , String [ ] methodNames ) { } void resetLabels ( ) { } String setMethodName ( String methodRoot ) { } String parameterInfo ( String methodRoot ) { } void getValue ( ) { } Class getReturnType ( String methodRoot ) { } void setValue ( ) { } Object [ ] parameterForType ( String typeName , String value , Control control ) { } void createOrientationGroup ( ) { } void createSizeGroup ( ) { } void createStyleGroup ( ) { } Composite createTabFolderPage ( TabFolder tabFolder ) { } void disposeExampleWidgets ( ) { } Image colorImage ( Color color ) { } Image fontImage ( Font font ) { } String [ ] getCustomEventNames ( ) { } int getDefaultStyle ( ) { } Control [ ] getExampleWidgets ( ) { } Item [ ] getExampleWidgetItems ( ) { } String getTabText ( ) { } void hookExampleWidgetListeners ( ) { } void hookCustomListener ( String eventName ) { } void hookListeners ( Widget widget ) { } void log ( Event event ) { } void log ( String string ) { } void log ( String eventName , TypedEvent event ) { } void recreateExampleWidgets ( ) { } void resetColorsAndFonts ( ) { } void setExampleGroupBackgroundColor ( ) { } void setExampleGroupBackgroundImage ( ) { } void setExampleGroupBackgroundMode ( ) { } void setExampleWidgetBackground ( ) { } void setExampleWidgetEnabled ( ) { } void setExampleWidgetFont ( ) { } void setExampleWidgetForeground ( ) { } void setExampleWidgetSize ( ) { } void setExampleWidgetState ( ) { } void setExampleWidgetVisibility ( ) { } void setExampleWidgetBackgroundImage ( ) { } }

Fix:
backgroundModeCombo = new Combo ( backgroundModeGroup , SWT . READ_ONLY ) ;